Resolving a small-bowel obstruction

Gastrointestinal obstructions are common, but an accurate diagnosis can prove tricky. Definitive therapy is not without challenges, and surgery can require complicated and frustrating postoperative care.

Diagnostics

Initial diagnostics in a vomiting animal should include abdominal imaging. Three-view abdominal radiographs and ultrasound are the most common forms of imaging.

Figure 1. Small intestinal foreign object (cloth) and evidence of mechanical obstruction

When evaluating abdominal radiographs, 2 populations of bowel are characteristic for a mechanical obstruction. Historically, in dogs, a ratio greater than 1.6 comparing the diameter of small intestine to the height of L5 vertebra has been recommended to determine presence of obstruction.¹ In cats, this has been reported as a ratio greater than 3.0 when comparing the diameter of small intestine to height of the cranial end plate of L2 vertebra.² However, more recent findings in literature have shown that objective ratios don’t provide more accuracy than subjective evaluation.³

Ultrasound provides enhanced information gathering regarding intestinal layering, location and type of obstruction, and evaluation of free fluid. Interpretation of ultrasound images is significantly affected by the skill level of the sonographer and this can affect accessibility for practitioners.

Figure 2. Small intestinal plication and foreign material, consistent with mechanical obstruction secondary to a linear foreign body.

Surgery

There are several intraoperative possibilities that must be discussed with clients, regardless of confidence in imaging. These include a gastrotomy, enterotomy, resection and anastomosis, milking the foreign body to the colon and removing transrectally, and a negative exploration.

Gastrotomy

Stay sutures using 3-0 or 4-0 monofilament placed on either end of the gastrotomy can be helpful to prevent spillage, as can suction and packing off with sponges. A stab incision should be made full thickness and extended as needed with scissors. Closure of the stomach is achieved with a 2-layer closure—most commonly a simple continuous closure for mucosa-submucosa and an inverting pattern for the seromuscular layer; however, multiple variations of closure are acceptable.

Enterotomy

Packing off the intestine prior to an enterotomy is prudent. In this author’s experience, the paper surrounding laparotomy sponges can be useful in minimizing contamination. The enterotomy should be performed aborad to the site of obstruction, so healthier tissues are available for closure. Closure can be performed in a simple interrupted or simple continuous fashion. An interrupted pattern is recommended for novice surgeons.

Intestinal resection and anastomosis

Figure 3. Segment of jejunum with foreign object isolated and packed off from the rest of the abdomen.

If the intestine is devitalized, or neoplasia suspected, a resection and anastomosis is indicated. Ingesta should be milked away and forceps placed to prevent leakage. The vessels supplying the portion of intestine to be resected should be ligated and transected. Hemostatic forceps are placed, and the intestine is incised orad to the orad clamp and aborad to the aborad clamp. There are multiple methods of anastomosis, including hand sewn (simple interrupted or continuous) and stapled. Although stapling has previously been questionable, research has shown that the likelihood of dehiscence is the same,⁴ if not lower,^5,6 when compared with hand sewn. When deciding to staple the intestine, an oversew of the transverse staple line is recommended to reduce the risk of dehiscence.^7,8

Tips and tricks

One method that is useful for linear foreign bodies is to suture the foreign object to a red rubber catheter. After releasing the anchor, the red rubber catheter is attached to the foreign material. The red rubber catheter is fed into the intestine and milked aborad. Sometimes this can be milked to the colon, avoiding the need for an enterotomy. More commonly, it is moved to healthier intestine where a single enterotomy can be performed, avoiding the need for multiple enterotomies.

Another technique that can make it easier to move foreign material in either direction is to inject a mixture of saline and sterile lube around the object. This gently distends the intestine to facilitate movement, and the lube eases transport.

One final trick that can make gastrointestinal surgery easier is performing the first half of a functional end-to-end stapled anastomosis (FEESA) prior to resecting the intestinal segment. This is performed by creating 2 stab incisions where the anticipated top (or belt) of the FEESA will belong and inserting and firing the stapler. After this, the resection can be completed, and a transverse anastomosis or gastrointestinal anastomosis stapler used to create the top (or belt).

Postoperative care

Postoperatively, patients should be provided with analgesics. Multimodal analgesia is considered standard of care, and combinations of transversus abdominis plane blocks, incisional bupivacaine (Nocita), as well as intravenous and oral analgesics are recommended. Pure mu opioids are commonly administered after gastrointestinal surgery; however, adverse effects include ileus and constipation. Antiemetics (maropitant, ondansetron) can be administered postoperatively and prokinetics considered on a case-by-case basis. Given that most of these patients present for vomiting, intravenous fluids should be continued after surgery until the patient is eating and drinking. Antibiotics are not indicated postoperatively unless gross contamination or other break in sterility has occurred.

The classical window of intestinal healing is 3 to 5 days. Any vomiting, lethargy, or changes in temperature should be taken seriously during this time point as they could be early indicators of intestinal dehiscence. Additionally, patient exercise should be restricted and the patient made to wear an Elizabethan collar for 10 to 14 days after surgery.

Rachel W Williams, DVM, DACVS (SA), is a clinical assistant professor of small animal surgery at the University of Florida. Her professional interests include urogenital surgery, minimally invasive surgery, and wounds and reconstruction. Outside the operating room, she enjoys being outside with her dogs, gardening, and traveling.

References

1. Graham JP, Lord PF, Harrison JM. Quantitative estimation of intestinal dilation as a predictor of obstruction in the dog. J Small Anim Pract. 1998;39(11):521-524. doi:10.1111/j.1748-5827.1998.tb03698.x
2. Adams WM, Sisterman LA, Klauer JM, Kirby BM, Lin TL. Association of intestinal disorders in cats with findings of abdominal radiography. J Am Vet Med Assoc. 2010;236(8):880-886. doi:10.2460/javma.236.8.880
3. Ciasca TC, David FH, Lamb CR. Does measurement of small intestinal diameter increase diagnostic accuracy of radiography in dogs with suspected intestinal obstruction? Vet Radiol Ultrasound. 2013;54(3):207-211. doi:10.1111/ vru.12032
4. Mullen KM, Regier PJ, Fox-Alvarez WA, Case JB, Ellison GW, Colee J. Evaluation of intraoperative leak testing of small intestinal anastomoses performed by hand-sewn and stapled techniques in dogs: 131 cases (2008-2019). J Am Vet Med Assoc. 2021;258(9):991-998. doi:10.2460/ javma.258.9.991
5. DePompeo CM, Bond L, George YE, et al. Intra-abdominal complications following intestinal anastomoses by suture and staple techniques in dogs. J Am Vet Med Assoc. 2018;253(4):437-443. doi:10.2460/javma.253.4.437
6. Davis DJ, Demianiuk RM, Musser J, Podsiedlik M, Hauptman J. Influence of preoperative septic peritonitis and anastomotic technique on the dehiscence of enterectomy sites in dogs: a retrospective review of 210 anastomoses. Vet Surg. 2018;47(1):125-129. doi:10.1111/ vsu.12704
7. Sumner SM, Regier PJ, Case JB, Ellison GW. Evaluation of suture reinforcement for stapled intestinal anastomoses: 77 dogs (2008-2018). Vet Surg. 2019;48(7):1188-1193. doi:10.1111/vsu.13274
8. Duffy DJ, Moore GE. Influence of oversewing the transverse staple line during functional end-to-end stapled intestinal anastomoses in dogs. Vet Surg. 2020;49(6):1221- 1229. doi:10.1111/vsu.13451